Sodium bicarbonate for runners: what's being used and what the research says
We report what runners are using and what the research says. We don't recommend taking any supplement. Talk to your GP or a registered sports dietitian before trying one.
Quick answer
Research suggests a small benefit in hard efforts of about 30 seconds to 12 minutes across sports[1]. Bicarb buffers the acid these efforts produce[1]. But in a 2025 meta-analysis of running trials, mostly under 5 minutes, the benefit was small and uncertain once likely publication bias was allowed for, and stomach upset was common[2].
- Research
- Emerging (proposed)Clear in short, hard efforts across sports. In running-only trials, mostly under 5 minutes, the effect was small or uncertain.
- Proposed by our editor; not yet confirmed by an expert reviewer.
- WADA status
- Permitted
- Distances in the research
- 800 m–5K: studied10K–half: limited researchMarathon: not studiedUltra: not studied
What is sodium bicarbonate?
Bicarbonate is made by the body and is a central part of the body's main pH buffering system[3]. Taking sodium bicarbonate before exercise raises the level of bicarbonate in the blood; across studies of buffering supplements, it rose by about 5 mmol per litre on average[4].
The Australian Institute of Sport puts it in Group A of its supplement framework, meaning strong scientific evidence for use in specific situations in sport, using evidence-based protocols[3].
Also called: bicarb, sodium hydrogen carbonate, NaHCO3.
Why is bicarb getting attention?
Bicarb is one of only a handful of performance supplements, along with caffeine, creatine, nitrate and possibly beta-alanine, that the IOC consensus statement says have good evidence behind them[5].
Its main drawback is stomach upset, and newer ways of taking it are being studied to reduce that, including enteric-coated capsules and mini-tablets inside a carbohydrate hydrogel[6]. In a 2024 trial, cyclists using the hydrogel form rode a 40 km time trial faster, with no significant difference in stomach symptoms from a placebo[7].
Running-specific research has grown too, from elite orienteers racing 3.5 km[8] to a 2025 meta-analysis of running trials[2].
How does bicarb work?
Hard running produces acid in the working muscles, and that build-up is linked to fatigue in efforts lasting a few minutes[1]. Bicarbonate in the blood acts as a buffer outside the muscle, which helps the muscle manage its own acid levels[5].
It is a buffer, not a fuel, which is why research has focused on short, very hard efforts rather than long, steady running[1].
Does bicarb work for runners?
Across sports, research suggests a small benefit in short, hard efforts[1]. In running, the only meta-analysis, mostly of efforts lasting 1 to 5 minutes, found no clear effect once likely publication bias was allowed for[2]. There is little evidence for longer running[9][10].
800 m to 5K (Studied)
Club to national standard runners were about 3 seconds faster in simulated 1500 m races after bicarb than after a placebo: 253.9 against 256.8 seconds on average[11].
Elite orienteers ran a 3.5 km time trial 6 seconds faster when bicarb was timed to each athlete's own peak blood bicarbonate, with the gain coming in the second half[8].
The ISSN position stand places the clearest effects in high-intensity efforts of about 30 seconds to 12 minutes[1].
10K to half marathon (Limited research)
Two small trials had trained runners hold a hard pace for 30 minutes and then run to exhaustion. Neither found that bicarb helped them last longer[9][10].
A meta-analysis of 189 studies found small average effects for efforts longer than 10 minutes as well as shorter ones, but it pooled many sports, not just running[4].
Marathon (Not studied)
We found no controlled trials of bicarb in marathon running. The running tests in the 2025 meta-analysis lasted between 1 and 30 minutes[2].
Ultra (Not studied)
We found no controlled trials of bicarb in ultra running. The same meta-analysis covered tests of 30 minutes or less[2].
The key studies, in order
- 1995TrialRunners were about 3 seconds faster in simulated 1500 m races after 0.3 g/kg than after placebo (253.9 against 256.8 s). [11]
- 1996Trial7 male runners held lactate-threshold pace for 30 minutes, then ran to exhaustion: no significant improvement with bicarb. [9]
- 2013Trial11 endurance-trained adults: one 0.3 g/kg serving did not change systolic blood pressure. Diastolic pressure rose 3.3 mmHg, and 10 of 11 had diarrhoea. [13]
- 2016Trial16 men: the rise in blood bicarbonate, and the time it took to peak (75 to 180 minutes at 0.3 g/kg), varied widely from person to person. [12]
- 2017Trial25 trained runners randomised, 18 analysed: no longer time to exhaustion after 30 minutes of hard running, a small rise in maximum speed. 15 had side effects, mostly stomach ache, diarrhoea or nausea; 7 stopped. [10]
- 2018ConsensusOnly a few performance supplements, including caffeine, creatine, nitrate and sodium bicarbonate, have good evidence. Responses vary between people, and contamination is a known anti-doping risk. [5]
- 2021Consensus0.2 to 0.5 g/kg improved high-intensity running, cycling, swimming and rowing, mostly in efforts of 30 s to 12 min. 0.3 g/kg looked optimal. Stomach symptoms were the most common side effects. [1]
- 2021Trial21 elite orienteers ran a 3.5 km time trial 6 seconds faster with bicarb timed to each athlete's peak blood bicarbonate, which came 60 to 180 minutes after taking it. [8]
- 2022Meta-analysis189 studies, 2,019 participants: buffering supplements raised blood bicarbonate by about 5 mmol/L and had a small overall benefit, with sodium bicarbonate the most effective. [4]
- 2024Trial14 trained male cyclists rode a 40 km time trial about 54 seconds faster after bicarb mini-tablets in a carbohydrate hydrogel, with no significant difference in stomach symptoms from placebo. [7]
- 2025Meta-analysis11 running trials, 126 people (84% men), tests of 1 to 30 minutes: a small benefit that became negligible after adjusting for stomach-related dropouts and likely publication bias. Stomach symptoms 29.5% v 2.6% (6 trials). [2]
- 2026Systematic review101 studies: common single servings (0.2 to 0.4 g/kg) caused mild to severe stomach symptoms, likely rising with the amount. Spreading intake, enteric coating and hydrogels were never compared directly. [6]
What the research can't tell us yet
The only meta-analysis limited to running pooled 11 small crossover trials with 126 participants, 84% of them men. The raw results showed a small benefit, but once dropouts with stomach problems and likely unpublished negative studies were allowed for, the average effect was negligible and not statistically clear. In the eight men-only studies it was small but clear[2].
Responses vary widely between people, including how far and how fast blood bicarbonate rises, so the same amount can have quite different effects in different runners[12][5].
Several running trials measured time to exhaustion on a treadmill rather than race times[9][10].
How is bicarb used in studies?
Most running studies used 0.3 g per kg of body mass, taken 60 to 146 minutes before the test, as a powder or in capsules with water or juice, usually without food[2].
The ISSN position stand describes 0.2 g per kg as the lowest single amount that improved performance in studies. Amounts above 0.3 g per kg added no benefit and caused more side effects[1].
Some studies spread the intake over 3 to 7 days before the test, split across meals, which may lower the risk of stomach problems on the day[1].
Because the time to peak blood bicarbonate ranged from about one to three hours between people, some research teams timed it to each athlete's own peak[12][8].
| What studies used | When | Ref. |
|---|---|---|
| 0.3 g per kg of body mass in most running trials (range 0.2 to 0.4) | 60 to 146 minutes before the test | [2] |
| 0.2 g per kg (lowest effective) to 0.3 g per kg (optimal) in one serving | 60 to 180 minutes before exercise (ISSN guidance) | [1] |
| 0.4 to 0.5 g per kg a day, split across meals | For 3 to 7 days before the test | [1] |
What are the side effects, and who should be careful?
Stomach problems are the main side effect: bloating, nausea, vomiting and stomach pain[1]. In the six running trials that reported them, 29.5% of people reported stomach symptoms after bicarb, against 2.6% after a placebo, and some dropped out because of them[2].
In one trial of endurance-trained adults, 10 of 11 had diarrhoea after a single serving[13]. Symptoms appear to increase with the amount taken at once[6].
Enteric-coated capsules, mini-tablets in a carbohydrate hydrogel and spreading intake over several hours have all been studied as ways to reduce symptoms. No study has compared them directly, so which works better is unknown[6].
Bicarb is about 27% sodium, so the amounts used in studies add far more sodium than the US upper limit of 2,300 mg a day[13]. In endurance-trained adults, one serving did not change systolic blood pressure, but diastolic pressure rose by about 3 mmHg and heart rate by about 10 beats a minute[13]. The effects of regular use on the kidneys have not been studied[1].
Be careful if
- You have high blood pressure or have been told to cut down on salt: the amounts studied are high in sodium[13].
- You have a kidney condition: the effects of regular use on the kidneys have not been studied[1].
- You have a sensitive stomach or a gut condition: stomach symptoms are common[2].
- You plan to use it in a race: the IOC consensus statement says supplements should be trialled in training before they are used in competition[5].
Is bicarb allowed in competition?
Sodium bicarbonate is not on the World Anti-Doping Agency's Prohibited List, so it is permitted in competition[14].
The anti-doping risk with any supplement is contamination. Products can contain prohibited substances that aren't on the label, and under the World Anti-Doping Code an athlete is responsible for anything found in their sample, even if it got there by accident[5].
Independent quality-assurance schemes, often called batch testing, check supplement products for prohibited substances[5]. WADA says using a product from one of these schemes can reduce, but not eliminate, the risk of an anti-doping violation[14], and the IOC says no product can be guaranteed entirely safe[5].
Myth or evidence?
5 things runners hear about sodium bicarbonate. Pick an answer to see what the research says.
1.Bicarb helps in any race, as long as you take enough.
Show the answer
Myth. Its effects are clearest in hard efforts of about 30 seconds to 12 minutes, and amounts above 0.3 g per kg added no benefit but caused more side effects[1].
2.Stomach problems are common after taking bicarb.
Show the answer
Evidence. In the six running trials that reported them, 29.5% of people reported stomach symptoms after bicarb, against 2.6% after a placebo[2].
3.Bicarb is banned in athletics.
Show the answer
Myth. Sodium bicarbonate is not on the WADA Prohibited List[14].
4.The same amount works the same way for every runner.
Show the answer
Myth. How far blood bicarbonate rises, and when it peaks, varies widely from person to person[12].
5.Bicarb makes a clear difference over the marathon distance.
Show the answer
Myth. We found no controlled trials in marathon running; the running trials in the 2025 meta-analysis lasted 1 to 30 minutes[2].
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Frequently asked questions
- Does bicarb work for runners?
- For short, hard races there is some evidence: runners were about 3 seconds faster over 1500 m in one trial[11]. Across running trials, most lasting under 5 minutes, a 2025 meta-analysis found the average benefit negligible once likely publication bias was allowed for, and stomach symptoms were common[2].
- Does bicarb help in a marathon?
- There is no direct evidence. The running trials in the 2025 meta-analysis lasted 1 to 30 minutes[2], and in trials where runners held a hard pace for 30 minutes before running to exhaustion, bicarb did not help them last longer[9][10].
- How common are stomach problems with bicarb?
- Common. In the six running trials that reported them, 29.5% of people reported stomach symptoms after bicarb, against 2.6% after a placebo[2]. In one trial, 10 of 11 adults had diarrhoea[13].
- Is bicarb banned in athletics?
- No. Sodium bicarbonate is not on the WADA Prohibited List[14]. The risk is contamination: a supplement product can contain a banned substance that isn't on the label, and athletes are responsible for anything found in their sample[5].
- How long before exercise do studies give bicarb?
- Most running studies gave it 60 to 146 minutes before the test[2], and the ISSN position stand describes 60 to 180 minutes[1]. The time to peak blood bicarbonate varies a lot from person to person[12].
References
- [1]
Grgic J, Pedisic Z, Saunders B, et al. International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance. Journal of the International Society of Sports Nutrition, 2021.
Consensus statement0.2 to 0.5 g/kg improved high-intensity running, cycling, swimming and rowing, mostly in efforts of 30 s to 12 min. 0.3 g/kg looked optimal. Stomach symptoms were the most common side effects.
doi.org/10.1186/s12970-021-00458-w - [2]
Miller LE, Bhattacharyya R, Katz SJ, et al. Negligible benefit of oral single-dose sodium bicarbonate on continuous running performance: systematic review with meta-analysis of randomized, double-blind, placebo-controlled trials. Journal of the International Society of Sports Nutrition, 2025.
Meta-analysis11 running trials, 126 people (84% men), tests of 1 to 30 minutes: a small benefit that became negligible after adjusting for stomach-related dropouts and likely publication bias. Stomach symptoms 29.5% v 2.6% (6 trials).
doi.org/10.1080/15502783.2025.2538606 - [3]
Australian Institute of Sport AIS Sports Supplement Framework: Group A and linked fact sheets. Australian Sports Commission, 2026.
Consensus statementLists sodium bicarbonate in Group A: strong scientific evidence for use in specific situations in sport, using evidence-based protocols.
www.ausport.gov.au/ais/nutrition/supplements/group_a - [4]
de Oliveira LF, Dolan E, Swinton PA, et al. Extracellular buffering supplements to improve exercise capacity and performance: a comprehensive systematic review and meta-analysis. Sports Medicine, 2022.
Meta-analysis189 studies, 2,019 participants: buffering supplements raised blood bicarbonate by about 5 mmol/L and had a small overall benefit, with sodium bicarbonate the most effective.
doi.org/10.1007/s40279-021-01575-x - [5]
Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. British Journal of Sports Medicine, 2018.
Consensus statementOnly a few performance supplements, including caffeine, creatine, nitrate and sodium bicarbonate, have good evidence. Responses vary between people, and contamination is a known anti-doping risk.
doi.org/10.1136/bjsports-2018-099027 - [6]
Winter IP, Sarac P, Wilson PB Gastrointestinal symptoms associated with sodium bicarbonate supplementation protocols: a systematic review. European Journal of Sport Science, 2026.
Systematic review101 studies: common single servings (0.2 to 0.4 g/kg) caused mild to severe stomach symptoms, likely rising with the amount. Spreading intake, enteric coating and hydrogels were never compared directly.
doi.org/10.1002/ejsc.70225 - [7]
Shannon ES, Regnier A, Dobson B, et al. The effect of sodium bicarbonate mini-tablets ingested in a carbohydrate hydrogel system on 40 km cycling time trial performance and metabolism in trained male cyclists. European Journal of Applied Physiology, 2024.
Randomised controlled trial14 trained male cyclists rode a 40 km time trial about 54 seconds faster after bicarb mini-tablets in a carbohydrate hydrogel, with no significant difference in stomach symptoms from placebo.
doi.org/10.1007/s00421-024-05567-3 - [8]
Lassen TAH, Lindstrøm L, Lønbro S, Madsen K Increased performance in elite runners following individualized timing of sodium bicarbonate supplementation. International Journal of Sport Nutrition and Exercise Metabolism, 2021.
Randomised controlled trial21 elite orienteers ran a 3.5 km time trial 6 seconds faster with bicarb timed to each athlete's peak blood bicarbonate, which came 60 to 180 minutes after taking it.
doi.org/10.1123/ijsnem.2020-0352 - [9]
Potteiger JA, Webster MJ, Nickel GL, et al. The effects of buffer ingestion on metabolic factors related to distance running performance. European Journal of Applied Physiology and Occupational Physiology, 1996.
Randomised controlled trial7 male runners held lactate-threshold pace for 30 minutes, then ran to exhaustion: no significant improvement with bicarb.
doi.org/10.1007/BF00599698 - [10]
Freis T, Hecksteden A, Such U, Meyer T Effect of sodium bicarbonate on prolonged running performance: a randomized, double-blind, cross-over study. PLOS ONE, 2017.
Randomised controlled trial25 trained runners randomised, 18 analysed: no longer time to exhaustion after 30 minutes of hard running, a small rise in maximum speed. 15 had side effects, mostly stomach ache, diarrhoea or nausea; 7 stopped.
doi.org/10.1371/journal.pone.0182158 - [11]
Bird SR, Wiles J, Robbins J The effect of sodium bicarbonate ingestion on 1500-m racing time. Journal of Sports Sciences, 1995.
Randomised controlled trialRunners were about 3 seconds faster in simulated 1500 m races after 0.3 g/kg than after placebo (253.9 against 256.8 s).
doi.org/10.1080/02640419508732255 - [12]
Jones RL, Stellingwerff T, Artioli GG, et al. Dose-response of sodium bicarbonate ingestion highlights individuality in time course of blood analyte responses. International Journal of Sport Nutrition and Exercise Metabolism, 2016.
Randomised controlled trial16 men: the rise in blood bicarbonate, and the time it took to peak (75 to 180 minutes at 0.3 g/kg), varied widely from person to person.
doi.org/10.1123/ijsnem.2015-0286 - [13]
Kahle LE, Kelly PV, Eliot KA, Weiss EP Acute sodium bicarbonate loading has negligible effects on resting and exercise blood pressure but causes gastrointestinal distress. Nutrition Research, 2013.
Randomised controlled trial11 endurance-trained adults: one 0.3 g/kg serving did not change systolic blood pressure. Diastolic pressure rose 3.3 mmHg, and 10 of 11 had diarrhoea.
doi.org/10.1016/j.nutres.2013.04.009 - [14]
World Anti-Doping Agency The Prohibited List. World Anti-Doping Agency, 2026.
RegulatorThe substances and methods prohibited in sport. Sodium bicarbonate is not on it.
www.wada-ama.org/en/prohibited-list
Who wrote and reviewed this
Written by Grant MacMillan, Editor, RunV. Not yet reviewed by an expert.
Last checked against its references . Next review due . How pages are reviewed · How we grade research
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